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.Dd October 14, 2006
.Dt DISKTAB 5
.Os
.Sh NAME
.Nm disktab
.Nd disk description file
.Sh SYNOPSIS
.In disklabel.h
.Sh DESCRIPTION
.Nm Disktab
is a simple database which describes disk geometries and
disk partition characteristics.
It is used
.\"by the formatter(\c
.\"IR.Xr format 8 )
.\"to determine how to format the disk, and
to initialize the disk label on the disk.
The format is patterned
after the
.Xr termcap 5
terminal data base.
Entries in
.Nm
consist of a number of `:'-separated fields.
The
first field for each entry gives the names by which a
disk's entry may be selected, separated by `|' characters.
The
last name given should be a long name fully identifying
the disk.
.Pp
The optional fields for each entry are:
.Bl -column "indent" "boolx"
.It Sy "ID	Type	Description"
.It "\&ty	str	Type of disk (e.g. removable, winchester)"
.It "\&dt	str	Type of controller (e.g."
.Tn SMD , ESDI ,
floppy)
.It "\&ns	num	Number of sectors per track"
.It "\&nt	num	Number of tracks per cylinder"
.It "\&nc	num	Total number of cylinders on the disk"
.It "\&sc	num	Number of sectors per cylinder, ns*nt default"
.It "\&su	num	Number of sectors per unit, sc*nc default"
.It "\&se	num	Sector size in bytes,"
.Dv DEV_BSIZE
default
.It "\&sf	bool	Controller supports bad144-style bad sector forwarding"
.It "\&rm	num	Rotation speed, rpm, 3600 default"
.It "\&sk	num	Sector skew per track, default 0"
.It "\&cs	num	Sector skew per cylinder, default 0"
.It "\&hs	num	Headswitch time, usec, default 0"
.It "\&ts	num	One-cylinder seek time, usec, default 0"
.It "\&il	num	Sector interleave (n:1), 1 default"
.It "\&d[0-4]	num	Drive-type-dependent parameters"
.It "\&bs	num	Boot block size, default"
.Dv BBSIZE
.It "\&sb	num	Superblock size, default 0"
.It "\&ba	num	Block size for partition `a' (bytes)"
.It "\&bd	num	Block size for partition `d' (bytes)"
.It "\&be	num	Block size for partition `e' (bytes)"
.It "\&bf	num	Block size for partition `f' (bytes)"
.It "\&bg	num	Block size for partition `g' (bytes)"
.It "\&bh	num	Block size for partition `h' (bytes)"
.It "\&fa	num	Fragment size for partition `a' (bytes)"
.It "\&fd	num	Fragment size for partition `d' (bytes)"
.It "\&fe	num	Fragment size for partition `e' (bytes)"
.It "\&ff	num	Fragment size for partition `f' (bytes)"
.It "\&fg	num	Fragment size for partition `g' (bytes)"
.It "\&fh	num	Fragment size for partition `h' (bytes)"
.It "\&oa	num	Offset of partition `a' in sectors"
.It "\&ob	num	Offset of partition `b' in sectors"
.It "\&oc	num	Offset of partition `c' in sectors"
.It "\&od	num	Offset of partition `d' in sectors"
.It "\&oe	num	Offset of partition `e' in sectors"
.It "\&of	num	Offset of partition `f' in sectors"
.It "\&og	num	Offset of partition `g' in sectors"
.It "\&oh	num	Offset of partition `h' in sectors"
.It "\&pa	num	Size of partition `a' in sectors"
.It "\&pb	num	Size of partition `b' in sectors"
.It "\&pc	num	Size of partition `c' in sectors"
.It "\&pd	num	Size of partition `d' in sectors"
.It "\&pe	num	Size of partition `e' in sectors"
.It "\&pf	num	Size of partition `f' in sectors"
.It "\&pg	num	Size of partition `g' in sectors"
.It "\&ph	num	Size of partition `h' in sectors"
.It "\&ta	str	Partition type of partition `a'"
.Pf ( Bx 4.2
file system, swap, etc)
.It "\&tb	str	Partition type of partition `b'"
.It "\&tc	str	Partition type of partition `c'"
.It "\&td	str	Partition type of partition `d'"
.It "\&te	str	Partition type of partition `e'"
.It "\&tf	str	Partition type of partition `f'"
.It "\&tg	str	Partition type of partition `g'"
.It "\&th	str	Partition type of partition `h'"
.El
.Sh FILES
.Bl -tag -width /etc/disktab -compact
.It Pa /etc/disktab
.El
.Sh SEE ALSO
.Xr getdiskbyname 3 ,
.Xr bsdlabel 8 ,
.Xr newfs 8
.Sh HISTORY
The
.Nm
description file appeared in
.Bx 4.2 .
